This Core will be responsible for collecting the patient samples needed for the successful prosecution of studies proposed in Projects 1 and 2. These will include large numbers of samples of DNA from organ transplant recipients and non-organ transplant recipients with non-melanoma skin cancers and from appropriately matched organ transplant recipients and non-organ transplant recipient controls without non-melanoma skin cancers. In addition, the Core will collect large numbers of non-melanoma skin cancers from organ transplant recipients and from non-organ transplant recipients from which DNA can be isolated. The Core also will collect from appropriate subjects fresh blood samples from which plasma will be isolated. The collections of such large numbers of samples will require collaboration not only with the UCSF Transplant Services but also with a number of Centers beyond the Bay Area, and in return for the needed collaboration, aliquots of some of these samples will be made available to investigators beyond the limits of the Program Project Grant.